The former Scotland under-21 international cancelled out Dean Cox's opener for the visitors as a match which had previously failed to capture the imagination burst into life.

Substitutes Stefan Scougall and Ben Davies both spurned chances to ensure United claimed maximum points but the contest finished all-square with Russell Slade's men losing ground in the race to overhaul second-placed Brentford.

Despite the high stakes - the Blades face Hull in the FA Cup semi-finals next weekend while Orient are chasing automatic promotion - the action was decidedly low key until Cox's 41st-minute effort.

Moses Odubajo launched a series of promising forays down the right flank but failed to apply the finishing touches while, at the other end, Ryan Flynn deposited a header straight into the arms of goalkeeper Jamie Jones.

With both teams looking to be solid first and spectacular second, it was always going to take something special to spark the match into life.

Moments later, the former England under-20 international saw his appeals for a penalty waved away by referee Michael Jones after tangling with the Orient defender.

John Brayford forced Jones to make a flying save as the hosts began to wrestle control. But, just as it seemed Clough's men were about to take charge, Cox pounced from close-range after Omozusi had recycled the ball following John Lundstram's blocked shot.

Clough, clearly unimpressed by his team's showing before the break, will have been encouraged to see them start the second-half in much more positive fashion with Stephen McGinn seeing a long-range effort deflected behind and Brayford unleashing a vicious first-time shot which was blocked.

United got their reward in the 63rd minute when Davies sent Murphy scampering through and, after beating both Mathieu Baudry and Jones, the Scottish winger scored his club's 7000th league goal.

Flynn saw a looping shot tipped over the crossbar as the hosts moved through the gears while Brayford should have edged United ahead after meeting Davies' free-kick only to glance his header wide.